Broaden Your Horizon by Wireless Network

——A Solution to Video Monitoring

Along with the intensifying competition in the market, the telecom operators are trying to extend their businesses into other derivative services from traditional voice and data services, in order to expand the scope of business and strengthen their competitive edge. The video monitoring service gradually becomes a key business to compete with for operators because it is widely used in different scenarios like education, government administration, water conservancy and power supply, oilfield exploration, military affairs, family affairs, urban traffic, community security, hotel management, sports and tourism as a solution of security, management and monitoring.

The deployment of traditional wired video monitoring system has many difficulties. For example, it costs a lot and takes a long time to lay cables in the traditional way as the points to be monitored are scattered and located far away from the master control center. Also it is hard to perform cabling work in the areas where mountains or rivers stand in the way. These problems have greatly impeded the development of video monitoring business.

The wireless transmission is bound to become a major transmission mode in the future. In wireless monitoring system, the wireless network generally acts as a data transmission link between monitoring points and the master control center that allows devices at remote monitoring points to transmit video signal through. As the video monitoring system requires high quality video images, how to ensure the transmission of high quality video in a stable manner in the wireless network becomes one of the key points for wireless monitoring system.

Currently the technologies such as microwave transmission, WiFi and CDMA-based 3G technologies (WCDMA, CDMA2000 and TD-SCDMA) are playing a leading role in the monitoring system. However, WiFi is apparently inefficient in wireless coverage of a large area though it has significant throughput. The microwave transmission has limited capacity because it can only be used in point-to-point control. Other 3G technologies are notably incapable to ensure the transmission of HD monitoring images which demands high throughput. For the details of comparison between different technologies, see Table 1 (deficiencies of existing wireless monitoring methods).

Table 1 Deficiencies of existing wireless monitoring methods

I.　　　 WiMAX – a technology more suitable for wireless video monitoring

According to the requirement for transmission media in video monitoring, the bandwidth is the most important bottleneck. Other factors include coverage, cost and capability of point-to-multi-point communication. With further analysis, the transmission technologies mentioned previously have more or less deficiencies in bandwidth, coverage, multi-point transmission capabilities and cost. Therefore it is impossible to carry out large-scale video monitoring business with wireless video monitoring system that adopts these technologies as transmission media.

However, we can see in Table 2 that WiMAX can offer a throughput of tens of mega-bits per second with similar coverage as that of 3G. The mechanism that assures five QoS guarantees more reliable performance of video monitoring service. Its capabilities to provide mobility and multi-user access make a perfect technical foundation to develop video monitoring business.

Table 2 Analysis of the advantages of WiMAX technology to video monitoring business

We can conclude by a general comparative analysis that the use of WiMAX as access method can reduce the cost of the construction of wired transmission system. User can perform video monitoring in a mobile vehicle. The soloution is scalable and easy to adjust. It can save the time, labor and engineering costs related to the deployment of the network cables.

The microwave transmission is more complicated than other traditional wireless monitoring technologies. It can only support point-to-point transmission in line of sight and it has to be fixed. WiFi transmits signals in a short distance. It is fixed and lack of a complete QoS mechanism. CDMA/WCDMA are inefficient in performing large scale HD monitoring because they are short in frequency spectrum effectiveness and data throughput. Therefore, WiMAX is more suitable for mobile video monitoring than the aforesaid wireless technologies.

The most workload is on the civil works of the monitoring points in the project of video monitoring. Also most of the investment is spent on the front-end equipments of the monitoring system. Usually the WiMAX wireless monitoring system consists of camera, encoder and WiMAX CPE at the monitoring point and base station at the master control center. The camera, encoder and CPE together constitute the front-end equipment in the monitoring system as indicated in Figure 1.

Figure 1 Diagram of the traditional WiMAX wireless monitoring system

The front-end equipment of this monitoring mode consists of camera, encoder and wireless transmission devices. They need to be installed separately at monitoring points, which will generate high cost for engineering works. Furthermore, the system is unreliable. It is complicated to maintain and the diagnosis is difficult when the system failure happens.

Therefore, the trend is to adopt integrated monitoring terminals in wireless monitoring system. The separated monitoring front-end equipment is considered only in some rare circumstances. The integrated monitoring terminal consists of the camera, encoder and transmission devices together. Its reduced size helps to save room and labor cost, and facilitates centralized management. Furthermore, the highly integrated equipment can be very cheap.

The integrated WiMAX monitoring camera MI100 of ZTE is shown in Figure 2. As an advanced monitoring terminal in the industry it is highly integrated, handy and extremely cost-effective.

Figure 2 ZTE WiMAX MI100 integrated video monitoring terminal

III. Complete Accreditation Billing Platform, a guarantee for scale operation

A powerful operation platform is the key to promote the civilian use of video monitoring and extend its application from specialized networks to public networks. ZTE has merged the operation and management platforms of video monitoring and WiMAX systems in order to realize unified management, billing and network administration.

The powerful business management system can facilitate massive user access, service access, user and service authentication management, tariff management, access control and alarm management. The system is also versatile in data collection and statistics to satisfy the needs of various applications that run on the platform. This can help to avoid double investment on management platforms in traditional solutions. The system also has interface to support various types of operational supporting system.

The accounting module supports full functionality of pre-payment, post-payment and payment by card and can interface well with the billing system.

A unified network management platform provides support to automated process management. It supports not only the protocols like SNMP but also the latest terminal management protocol TR069 to enable unified network management of the streaming media server, the disk storage system, the PU device and CU device that are involved in the video monitoring operation. The system can be integrated into the existing unified network management platform of telecommunication operators to achieve unified management. The PU/CU devices of the video monitoring system have intelligence and their configuration and control are complex. Installed scattered with large quantity at the outdoor monitoring points or next to the users, an efficient method is necessary in order to facilitate the management of terminals. The network management system “Network Video” can manage and maintain efficiently and promptly PU/CU with the network management protocol TR069. Extensive management measures help to transform from pure equipment management to business management.

IV.　 Extensible Scalable Network Structure Topology to Facilitate Flexible Network Deployment

Since the front-end monitoring points are always expanding, we have to install the front-end devices whenever a new monitoring point is added. But the master control center expands only when the number of monitoring points reaches certain threshold. For example, a master control center does not need to be expanded until another 8 or 16 monitoring points are added. Therefore, it is necessary to take the network layer into consideration. The expansion of each network layer needs to be modularized.

Operatable network structure

The system design of ZTE WiMAX based on end-to-end video monitoring solution follows the philosophy described previously. As shown in Figure 3, the whole network is divided into supporting layer, media exchange layer and user device layer (front-end and user-side).

Figure 3 ZTE WiMAX video monitoring system

The supporting layer can be set up all at once and its service can not be opened to the public until it gets powerful operation management capabilities. The supporting layer of Wi-Eye system is composed of the management platform of video monitoring service and operation supporting system. The major modules include operation platform and equipment management platform that performs equipment management and control, alarm, dispatch, access authentication and network management.

The media exchange layer consists of media distribution network. It works as a media distributor and network storage manager. The ZTE wireless video monitoring solution has distributed architecture. The solution provides the forwarding, distribution and storage of the monitoring media, the processing and control of monitoring video, and it support access-on-need of different users. The quantity of network elements in media exchange layer can be expanded at certain scale and the modification will not affect the operation support layer and the user equipment layer.

The user equipment layer is composed of PU front-end and CU client equipments which are located at the monitoring point of the user and the master control center respectively. The user can realize the image upload from the monitoring points by PU front-end equipment and real time monitoring and background control of every monitoring point by CU client.

 Layered expansion method

The ZTE Wi-Eye video monitoring system can be deployed in a distributed way. The system expansion and upgrade are smooth. The design of distribution network is hierarchical and distributed. It builds a forwarding network by deploying the streaming media servers in different layers. Followed by the expansion of monitoring application, two methods are supported

Ø　Increase the stream capability of individual node, increase the capability to support more concurrent streams by adding extra stream media servers.

Ø　Increase the number of nodes to expand the stream concurrent capacity of the whole system, for areas where the number of the users increase rapidly, increase the number of node at edge to achieve linear increase of various demands

The distributed configuration of business operation platform can realize smooth expansion of registered management modules in response to the growth of the system size and applications.

In both expansion methods, the stream service, the storage equipment, the PU front-end and the CU client can each expand its capacity in every possible way without restructuring the original system to ensure the smooth progress of the business.

The wireless network monitoring system adopting WiMAX wireless transmission technology can better share the transmission line in order to combine adequately the special and public networks.  It can generate great business opportunities to operators by introducing video monitoring to civilian applications while bringing down the application cost of the special networks.

The WiMAX-based end-to-end wireless video monitoring solution of ZTE combines the advantages of the monitoring system (including different aspects of the platform) and that of WiMAX technology. Four advantages of the solution are cost-effective, high quality, easy to operate and manage. Without sacrificing the monitoring performance the solution can reduce the operation cost and make the system easier to operate at the same time.